The Skull Theory

For Fun Or Science?

This theory continues to fascinate mothers-to-be, as many claim this at-home technique can be up to 92% accurate. While we cannot corroborate this statistic with significant evidence, this may be a helpful indicator when trying to predict the sex of your baby – Just for fun.

Male and Female Cranium Differences:
Most important skull differences between men and women are indicated by the letter value on the figure to the left and described below:
A) The male cranial mass is more blocky and massive compared to the females, which is rounder and tapers at the top.
B) Temporal Ridge – this runs along the outer side of the upper skull creating the square shaped of the upper head. More prominent in men than women.
C) A woman’s supraorbital margin (the ridge above the eyes) is sharper, while the males is round and dull.
D) The Zygomatic bone (the cheekbone that lies under the lower eye ridge) is more pronounced on the male skull.
E) The Mandible (lower jaw) bone of a woman is rounded, while the male’s is squared.
F) Frontal bone forehead structure terminates at the brow. The male forehead is lower and more sloping.
G) Men have a deeper cranial mass.
H) The supercilary arch is large and pronounced in the man.
I) A males gonion (most posterior inferior point on angle of mandible) is more flared out and sharply angled.
J) The teeth of men tend to be larger.


As you might imagine, analyzing a skull via ultrasound can be tricky, but the skull differences mentioned above can help with predicting the sex of your baby! The best time to test the skull theory is after 12 weeks gestation. If you are still unsure, The Nub Theory Experts may be able to help!

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Disclaimer: Our website is intended for entertainment purposes only.
All though we are confident in our methods no gender is 100% accurate until birth.